Crankcase Breather / oil catch tank

TwoWheelTerror · 13 Dec 2006, 13:32 (Ref:1789852)

I know the benifits of not burning oil vapour in a performance engine..

My current set up involves an oil catch tank with a green filter venting on top venting to atmosphere. But I'm told (by a keyboard warrior on another forum) that "in 'proper' setups the now non-oily vapour is directed back to the inlet"

Now my thinking is that while the oil may mostly have condensed in the catch tank it would still affect the combusion mixture.

What do people on here think / do?

graham bahr · 13 Dec 2006, 14:09 (Ref:1789883)

stick with the current set up you have, its in the best possible interest of your engine if not the atmosphere! but then again, whats a few fumes coming out a breather compaired to whats coming from your exhaust

greenamex2 · 13 Dec 2006, 16:26 (Ref:1789940)

Your current is standard race practice at all levels. Leave it as it is and ignore him.

trikesrule · 14 Dec 2006, 09:58 (Ref:1790449)

On our three Speedway cars we run Crank Vents. These devices create a negative pressure in the crankcase. Worth 2.9 kw on the dyno (at the wheels) ($75 aus) and we have no fumes in the engine bay at all and best of all - no oil leaks. Only thing is, we learn't pretty darn quickly how to build our engines to be air tight (does that make sense?). Cork sump gaskets no na no. A fumy engine is not a good sign to me. I'd be looking for the reason(s) an engine has blow by........trikes

terence · 14 Dec 2006, 20:01 (Ref:1790817)

Totally fumeless engine,now theres a thought.

**dtype38** · 15 Dec 2006, 17:55 (Ref:1791599)

Aha... talking of "fumeless" engines, has anybody here tried TotalSeal Piston rings. They're an Aussie product which claim to eliminated piston ring blowby. I'm interested because it should improve volumetric efficiency as well as cut down on oil breathing. A cleaner more powerful engine by just changing piston rings?

R59 · 15 Dec 2006, 21:45 (Ref:1791762)

Trikesrule - what you are doing there is much the same as circle track methods use Stateside. At one point, NASCAR teams were running 7 stage dry sump pumps. One pressure, three scavenge, and the other three pulling vacuum in the rest of the motor. The problem is that with too much vacuum in the crankcase, you stand a chance that you'll pull the flamefront past the piston into the sump which contains a fair amount of vapour/fumes. These ignite, and kabooom! Big flaming blowup.

NASCAR banned pumps of more than 5 stages for that reason.

I currently run a 3 stage pump on my Chevy, it pulls a slight vacuum, If I go to a 4 stage (next plan) it'll pull a little more.

I have some genuine NASCAR spec composite valve cover gaskets for that - they are very rigid - like you say - cork is useless! I use Silicon Rubber Composite on my valve covers, they have the benefit of being re-useable.

Moving back to the thread....

On drag engines, the breaters are connected to the exhaust headers. It generates vacuum in the breather pipes, and sucks the fumes into the exhaust, where they are burned off in the heat of the exhaust.

I've never tried Total Seal rings. I've seen the ads, read the blurb, but never had "you must use these - they're the biz" from any builders I know and trust.

Rob.

terence · 16 Dec 2006, 08:10 (Ref:1791964)

Quote:

Originally Posted by dtype38

Aha... talking of "fumeless" engines, has anybody here tried TotalSeal Piston rings. They're an Aussie product which claim to eliminated piston ring blowby. I'm interested because it should improve volumetric efficiency as well as cut down on oil breathing. A cleaner more powerful engine by just changing piston rings?

Totally recomend them,I,ve used them for the last 4yrs,no problems at all.I do still get fumes though ,only to be expected from a 50yr old engine design I suppose.

**dtype38** · 16 Dec 2006, 12:09 (Ref:1792053)

Will probably get the same with my engine. Not sure how old the design is, but the engine itself is coming up to 42 years old. Now if I can only get them to reply to my emails...

terence · 16 Dec 2006, 17:08 (Ref:1792202)

I think MASS RACING have a direct line to them,worth a try?

**Tim Falce** · 16 Dec 2006, 17:53 (Ref:1792217)

Quote:

Originally Posted by dtype38

Will probably get the same with my engine. Not sure how old the design is, but the engine itself is coming up to 42 years old. Now if I can only get them to reply to my emails...

The design is now 60 years old or probably more. I think you can get a similar type of ring here, if they still make them that is.

ian_w · 16 Dec 2006, 20:57 (Ref:1792320)

I've run some 'Total Seal' rings in the past and they produced very similar performance to the regular top ring used in the engine. No change was seen in the blowby or crankcase pressure from the engine either. So overall, no improvement and they were never raced.

The theory sounds appealling for the ring but in reality the lost of combustion gas thro a conventional ring is very small. The engine in question consumed about 18000 litre/min of air yet blowby was less than 80 l/min, i.e. 0.4%. So even if you could get zero blowby then the performance increase would be very small.

The rings are certainly not a disaster but they are not the 'Holy Grail' either. If you are happy using them then carry on but I wouldn't go to a huge effort to convert your engine to use them.

Notso Swift · 16 Dec 2006, 23:58 (Ref:1792402)

I know these guys, they are in Bayswater and when I was at Uni I use to deliveries for the guy who suppplies 90% of their other engine parts. (There is also an associated company in Phoenix)
Anyway we tried this on a number of motors, personally on my old Mini, and I would say the results were marginal. No worse than a well bedded in conventinal ring, but not significantly better. I think a Dykes ring is better.
Where I think they do work if for motors that run heaps of fuel, like drag motors on alcohol or methanol, reason being is that you want to actively stop the flow of fuel into the oil, but on petrol, even my turbo rarely runs much richer than 11:1.
With gas the ring can still flutter and the gas still gets behind the ring. So for me they are not quite worth the money, but I can see how some think they are.

**dtype38** · 17 Dec 2006, 08:11 (Ref:1792534)

Thanks for that NS, I follow your reasoning. Their lack of response to my enquiry doesn't exactly fill me with confidence either, so I think you just saved me a fair bit of work. Ta

**Tim Falce** · 17 Dec 2006, 08:23 (Ref:1792541)

Quote:

Originally Posted by ian_w

The engine in question consumed about 18000 litre/min of air yet blowby was less than 80 l/min, i.e. 0.4%. So even if you could get zero blowby then the performance increase would be very small.

ian, without making me go to sleep with lots of equations and engineers speak, how do you measure blowby. What would you use to mesure the amount of air that gets past the rings?

ian_w · 17 Dec 2006, 10:30 (Ref:1792661)

The engines I work on are all dry sumped. What we do is connected an air flow meter to the top of the oil tank and then vent this to atmosphere. The crankcases are fully sealed so any gas that gets to the tank must have come past the piston rings.

On a wet sump engine you would simply connect the air flow meter to the crankcase ( making sure that you have blanked off any breathers that go to the inlet manifold ).

We use two different types of meter, one is a purpose designed 'blowby' meter ( very expensive ) and the other is a general purpose 'turbine' type flow meter. You can also use such things as a simple orifice plate flow meter or I have even heard of people using old gas meters. You need to avoid hot wire type meters as these will be contaminated by the oil in the blowby gas.

It should be noted that Total Seal sell a variety of different types of 'conventional' piston rings as well as their 'gapless' variety.

**Tim Falce** · 17 Dec 2006, 10:38 (Ref:1792665)

Ian, thanks for that.

trikesrule · 17 Dec 2006, 20:40 (Ref:1793045)

Check this out www.KrankVent.com .........trikes

Al Weyman · 17 Dec 2006, 22:22 (Ref:1793133)

I have used the gap less rings, good figures on a leakdown test but that may have been more down to honing with honing plates bolted down to correctly distort the bore in an 'as used' spec. I have used the crancase evacutor kit as well in the past and it is good for getting a nice dry engine if nothing else!

ian_w · 18 Dec 2006, 17:25 (Ref:1793799)

Quote:

Originally Posted by trikesrule

Check this out www.KrankVent.com .........trikes

Sounds a bit like 'snake oil' to me. The only way you can generate a crankcase vacuum without a scavenge pump system is to pull the crankcase pressure down by connecting it to the inlet manifold. However at full throttle you don't really have any manifold vacuum so you won't get any crankcase vacuum when you most need it. Also if you start trying to pull large amounts of air out the crankcase and into the inlet you will inevitably pull thro a load of oil which is bad news from a detonation point of view. The only thing that sounded vaguely plausable was limiting the amount of air enter the crankcase on turbo engines when on boost. I think I'll keep my $100+ in my pocket!

Chris Y · 18 Dec 2006, 18:03 (Ref:1793831)

Quote:

Originally Posted by ian_w

The only way you can generate a crankcase vacuum without a scavenge pump system is to pull the crankcase pressure down by connecting it to the inlet manifold.

What about the exhaust manifold then?

ian_w · 18 Dec 2006, 18:34 (Ref:1793850)

The KrankVent system was very vague about how it worked but did say it wasn't connected to the exhaust.

You can use exhaust exhaust pressure pulses but I doubt you could really generate any significant vacuum with this or the KrankVent system.

trikesrule · 18 Dec 2006, 20:07 (Ref:1793959)

Hi ian-w ? When using the exhaust to scavenge wouldn't part of the exhaust pulse return up the hose? Just curious. The Krankvent is a neat, tidy installation and works amazingly well and provides clean oneway evacuation of the crankcase. I have one on my dodgey old ute and the wifes car as well as all our race engines and I've another one for my tow car. Very very pleased with the dollar value of performance / efficiency gained (dyno proven).......trikes

Chris Y · 19 Dec 2006, 08:42 (Ref:1794346)

Ignoring the KrankyVent for a moment, perhaps a tube attached to the exhaust with some form of one-way valve would be a better proposition for producing negative crankcase pressure than connecting it up to the inlet tract - particularly in view of the lack of vacuum in the inlet at WOT.. ?

trikesrule · 19 Dec 2006, 09:08 (Ref:1794365)

What do u think a krankvent is? It's a one way indesructable valve.....trikes

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